1. Field of the Invention
This invention relates to methods for producing materials and is particularly directed to an improved method for producing NF.sub.4 PF.sub.6.
2. Description of the Prior Art
Nf.sub.4.sup.+ salts are the key ingredients for solid propellant NF.sub.3 --F.sub.2 gas generators, such as that taught by D. Pilipovich in U.S. Pat. No. 3,963,542 for chemical HF--DF lasers. Whereas NF.sub.4 SbF.sub.6 and NF.sub.4 AsF.sub.6 can be prepared with relative ease, using the methods of W. E. Tolberg et al, U.S. Pat. No. 3,708,570, and K. O. Christe et al, U.S. Pat. No. 3,503,719, these compounds suffer from the disadvantage of containing a relatively heavy anion, thus decreasing their performance in an NF.sub.3 --F.sub.2 gas generator. This disadvantage can be overcome by replacing the SbF.sub.6.sup.- or AsF.sub.6.sup.- anion by the lighter PF.sub.6.sup.- anion. The existence of this salt has previously been claimed by Tolberg et al. (U.S. Pat. No. 3,708,570), but their production process was so inefficient that they could not isolate an amount of material sufficient for its isolation, identification, and characterization.